Not all fats are bad for you. While you should limit saturated and trans fats, the unsaturated fats -- including the polyunsaturated omega-3 and omega-6 fats and the monounsaturated fats, or omega-9 fats -- are healthy in moderation. Including at least small amounts of these fats as part of a reduced-calorie diet may help make your meals more satisfying and make losing weight easier.
Omega-3 fats are essential fats your body needs for brain development that may also help limit your risk for heart disease. Good sources include flaxseeds, walnuts, salmon, herring, tuna, mackerel, sardines and other fatty fish. The Academy of Nutrition and Dietetics recommends getting at least 500 milligrams per day of EPA and DHA, the main omega-3 fats found in seafood.
Getting plenty of omega-3 fats in your diet may help increase your feelings of fullness, making it easier to lose weight and keep it off, according to a study published in Appetite in November 2008. A review article published in Nutrients in 2010 noted that omega-3 fats may help with weight loss by reducing appetite and increasing fat burning, especially when combined with a reduced-calorie diet and exercise.
Not all studies point to weight-loss benefits, however. For example, a study published in The American Journal of Clinical Nutrition in December 2010 found no differences in weight loss between people following a diet and exercise plan who took omega-3 supplements and those given a placebo.
Omega-6 fats are essential as well, but most people get more of these than they need in their diets. A high ratio of omega-6 to omega-3 fats, such as that found in the typical American diet, may increase inflammation and your risk of cancer, heart disease and arthritis. If you're trying to lose weight, it may be best to limit your omega-6 consumption, which can cause you to retain water. Aim for a 3-1 ratio of omega-6 to omega-3 fats, recommends Unity Health System. These fats should make up between 5 and 10 percent of your total calories for the day. Some of the main sources of omega-6 fats include soybean oil, safflower oil and corn oil.
These monounsaturated fats aren't essential, as your body can make them, but they're one of the healthiest types of fat. They potentially increase your high-density lipoprotein, or "good" cholesterol, while decreasing your low-density lipoprotein, or "bad" cholesterol. A diet with moderate amounts of fat from monounsaturated fats can help you lose a similar amount of weight as a low-fat diet while decreasing your risk for heart disease because of these beneficial changes to your cholesterol levels, according to a study published in The American Journal of Clinical Nutrition in February 2004.
Most of your fat should come from monounsaturated fats, with these fats making up between 12 and 20 percent of your total calories, recommends the University of Illinois Extension. Good sources include nuts, olive oil, canola oil, avocado and olives.
Although some fat is needed for a healthy diet, you don't want to overdo it. Limit your total fat consumption to no more than 20 to 35 percent of calories. That's 44 to 77 grams for a 2,000-calorie diet. You'll also need to limit your caloric intake to lose weight, cutting between 500 and 1,000 calories out of your diet each day to lose weight at a healthy rate of 1 to 2 pounds per week. Cut back on sweets and highly processed foods to do this, rather than decreasing your intake of healthy and relatively low-calorie fruits and vegetables.